Reflector for automobile headlights



Oct. 8, 1929. v v c. B. HAMILTON 1,730,571

REFLECTOR FOR AUTOMOBILE HEADLIGHTS Filed Jan. 7, 192's Patented Oct. 8, 1929 PATE T Price CURTIS B. HAMILTON, OF WALDEN, COLORADO REFLECTOR FOR AUTOMOBILE 'HEADLIGHTS Application filed. January 7, 1928. Serial No. 245,082.

This invention relates to improvements in reflectors for automobile headlights.

It'is a nortorious fact that the greatest danger attendant upon night driving of antomobiles is theblinding effect due to the glare from the headlight-s of approaching automobiles.

It is the object of this invention to produce a reflector suitable for use in connection with automobile headlights and which shall be so constructed that it will throw a well distributed light over the road in front of the car and to a suflicient distance ahead to permit drivingat high speed and which will also throw light to the sides of the road so as to permit safe turning.

It is a further object of this invention to produce a reflector that will satisfactorily illuminate the road without casting objectionable upwardly'directed rays that blind approaching drivers.

I have found that in order to obtain the desired results, it has been necessary to depart almost entirely from the established practice and to resort to curves that are especially designed to produce the result desired instead of employing some fixed mathematical curve which is inherently unadapted to produce the desired effect.

Owing to the fact that my reflector departs widely from present practice, its shape can only be described when reference is had to the accompanying drawing in which it has been illustrated to scale, the parts being shown one-half actual size and in which:

Fig. 1 is a View looking into the reflector;

Fig. 2 is a vertical section taken on line 2-2, Fig. 1;

Fig. 3 is a transverse section taken on line 33, Fig. 1;

Fig. i is a transverse section taken on line 44,Fig. 1;

b 1g. 5 is a transverse section taken on line 55, Fig. 1;

Fig. 6 is a transverse section taken on line 66, Fig. 1;

Fig. 7 is a diagrammatic view looking down onto the reflector and illustrates the latera distribution of the light rays; and

Fig. 8 is a side elevation showing the vertical distribution of the light. I

My improved reflector is shallow when compared to the usual paraboloidal reflector and instead of being circular when viewed from the front, it has the appearance illustrated in Fig. 1 from which it will be seen that that portion located above the section line 33, is a semi-circular arc in. outline, which has been designated by numeral 1. From section line 33, the sides 2 are straight down to the points designated by numeral 3. That part of the reflector below section 55 is preferably a circular arc in outline and is joined to sides 2 by a curve 4. The' lamp1 socket 5 and the lamp 6 are located at the center of the are 1. The curvature of thereflecting surface of that portion marked A, of the reflector above section line 38, is such that it reflects all of the light rays convergently in the manner shown in Fig. 2 in which 7 represents the direct and 8 the reflected'rays. The reflected rays are, however, not parallel but make different angles with the axis of the lamp in the manner shown in Fig. 3 where 7, 7 and 8, 8 are representative rays illustrating the properties of that part of the reflector above the section line 33. Attention is called to the fact that the curvature increases towards the edges of the reflector so that the rays that strike the reflecting surface near its outer edgeare reflected at a sharper angleand therefore the reflectedrays from the different zones cross in front of the reflector. The rays reflected from the zones near the axis of the lamp are more nearly parallel with the axis of the reflector than those reflected from zones farther away. The rays that are represented by 8- are therefore the ones that strike the road nearest to the automobile, while those that are reflected from the smaller zones are the ones that illuminate the road farthest ahead. Attention is called to the fact that since the upper half of the reflector throws no divergent rays, it is impossible to get objectionable glare from this part of the reflector. Itis evident, however, that if the reflector were symmetrical with respect to section line 33, that some of the rays reflected by the lower portion would cause highly objectionable glare. The part of the reflector below line 33 has, therefore, been so designed that all of the light that strikes it will be reflected in a downward direction. That portion of the reflecting surface bounded by the dotted line 9 and which has been designated by B is slightly concave in a transverse direction in the manner illustrated in Figs. 4, 5 and 6, and is inclined downwardly at such an angle that all of the light that strikes it is reflected in a downward direction in the manner shown in Fig. 2, where 10, 10 and 10? indicate the direct rays and 11, 11 and 11 the reflected rays. It is evident that there can be no objectionable glare from surface B as there are no upwardly directed reflected rays. The two areas C that are bounded by line 9, section 3 and the edge of the reflector can be of any curvature which will conform to the curvature of the parts with which they are connected. As areas C are below line 33, it is almost impossibleto get upwardly directed reflected rays of light from them without resorting to special shapes for this purpose. The light that strikes surface C is directed sideways and downwardly and the genera form of the light paths for surface C is illustrated in Fig. 1 where 12 and 13 represent the direct and the reflected rays.

It will be apparent from the above description that my improved reflector is so formed that it has four areas that have distinct properties. That portion above the section line 33, reflects convergent rays; that portion below section line 33, and within line 9 reflects downwardly divergent rays while the two areas C reflect downward convergent rays. Another peculiarity of reflecting surface A is that the reflected light from the different zones intersect each other.

Reflectors constructed in the manner described give good illumination over the entire road and the rays from the zones nearest the center of the reflector serve to illuminate the road a considerable distance ahead for fast driving while light from the zones adjacent the edge illuminates the sides of the road and the road surface directly in front of the car.

Having described the invention what is claimed as new is A reflector having a concave reflecting surface that is unsymmetrical with respect to the source of light and with a horizontal plane passing through the source of light but symmetrical with respect to a vertical plane passing through the source of light, that portion of the reflecting surface above the horizontal plane having substantially similar arcuate sections in spacedparallel planes that are perpendicular to the line of intersection of the horizontal plane and the vertical plane of symmetry, the size of said sections increasing towards the front of the reflector, that cunrrs B. HAMILTON. 

